题目

已知集合 . （1） 当 时，求 ； （2） 若 ，求实数 的取值范围. 答案：当 m=1 时， B={x|m−3≤x≤2m+1}={x|−2≤x≤3} . 因为集合 A={x|−1≤x≤4} ，所以 A∩B={x|−1≤x≤3} . 由 A∪B=B ，则 A⊆B ， 所以 {m−3≤−12m+1≥4m−3≤2m+1 ，解得 32≤m≤2 ， 所以实数 m 的取值范围是 32≤m≤2 .As traditional Chinese art, paper cutting has a long history. The first and earliest paper cutting was found in China 1,500 years ago. But this traditional art is at risk of disappearing now. Luckily, Voyo Woo, a Chinese immigrant（移民）in America, is trying to bring this art back to life.One Saturday in 2014, Ms Woo held a paper cutting show at a shopping center near Washington. She got much fun and peace doing it. She hoped more people would enjoy it.Ms Woo began to study the art of paper cutting as a 14-year-old girl in her hometown in China. She said all the students at school had to learn paper cutting. But she had a deep love for it. So her teacher spent more time teaching her after class. Later, she won the second prize in a national painting and art competition. Ms Woo went to America after she finished collage in 2008. Soon after that, she took part in an activity to promote（宣传）Chinese paper cutting. And then she was invited to show the art in many important activities.“It is important to promote this art to Americans or anyone who is interested in it.Maybe it will make this art more popular.”Woo said.From the art of paper cutting, people can know about Chinese cultural values, history and stories of people’s life. Ms Woo uses the art as a tool to show Chinese culture to people who know little about it. Chinese art is not only for Chinese, but also for people all over the world.【1】What did Ms Woo do in 2014?A. She won the second prize in a national painting and art competition.B. She was invited to many activities to show paper cutting.C. She held a paper cutting show at a shopping center near Washington.D. She took part in an activity to promote Chinese paper cutting.【2】Ms Woo began to study the art of paper cutting .A. when she was fourteenB. after she got to AmericaC. when she was in collegeD. after she finished college【3】In the passage, the writer thinks the art of paper cutting is now.A. very popular in America B. very popular in ChinaC. for people who know about it D. in danger of disappearing